Intermitant heating/cooling problem.

[whtefbrd96]

96 3.8 automatic with 140,000 miles. New thermostat (180 degrees) and water pump 10,000 mile ago. About 20 degrees outside temp.

Last night i was driving about 60 mph and i noticed my temp gauge starting to climb and my heat started blowing COLD air the temp gauge went to about 230 and just as i was about to shut off the engine the heat came back to life and the gauge plumeted down to like 170 which is below where it normally rests. And it would do this randomly at this speed or any other speed below it. Well i got on the interstate and got up to my normal cruising speed of 70-75 for the ENTIRE time i was at this speed the heat worked fine and the car ran about 180 but as soon as i dipped much below that it started acting up again.

So who is with me in believing it is the thermostat? And also is there some electronic sensor other than the mechanical thermostat that can control the coolant flow from the engine to the radiator?

I would just have thought the gauge was messed up with it moving as fast and irradic as it was but the whole heat going from cold to hot really let me know that wasnt the problem.

thanks for any help !

[ January 31, 2004: Message edited by: whtefbrd96 ]</p>

[njspder]

have you had the cooling system back flushed? it almost sounds liek crud is getting stuck and causing a blockage then breaking free and lettting coolant flow again.
the stat is the only thing in the cooling system controlling the volume of flow, everything else that gm put there is just sensors and fan swithes.
i would suggest flushing the system completely and throwing in a new stat.

later
tim

[whtefbrd96]

Well i have some depressing news.... today i checked my coolant, only to find it about a GALLON low :eek: so i filled it up and drove it everything was fine.... well except for the fact that i cant figure out where the coolant leaked from. I know its from the front of the engine more towards the drivers side. Its not the water pump or any hoses ( cause that would be just too phucking simple ) :mad: i cant see exactly where its coming from but it is dripping down the engine enough that it is beading up on a sensor for the power steering pump then coating the oil pan and transmission pan and has some random splatters under the car...... [img]graemlins/crybaby.gif[/img]